1. Field of the Invention
The present invention relates to a projection light module for a motor vehicle headlight according to the preamble of claim 1.
2. Description of the Related Art
One representative example of a projection light module of the type generally known in the related art is disclosed in DE 10 2011 012742 A1 and is adapted to generate an inner light distribution in its interior. It has a secondary lens system, which is constructed and arranged to project an image of the inner light distribution as an external light distribution into the outside perimeter of the projection light module. It further has a low-beam light diaphragm which, with a proper use of the projection light module installed in a headlight, separates the low-beam light volume located above this diaphragm from a high-beam volume of the projection light module located below this diaphragm. In the high-beam volume is arranged a high-beam diaphragm which at the aforementioned use comprises a diaphragm edge extending more vertically than horizontally, and which separates the high-beam volume into a right high-beam volume located to the right of the high-beam diaphragm and a left high-beam volume located to the left of the high-beam diaphragm. The diaphragm edge is so arranged that it is displayed by the secondary lens system in the external light distribution as a more vertically than horizontally extending bright-dark boundary.
In the last few years, headlights have been available on the market which perform lighting functions, which are controlled by a camera-based image analysis of the scene in front of the motor vehicle.
Under a light function we understand the production of a light distribution by the headlights. Examples of light distributions are low-beam light distributions and high-beam light distribution.
For example, the control allows an automatic high-beam circuit with a partial beam function, which ensures that, despite oncoming cars and/or cars driving in front of the vehicle, a part of the high beam can remain active. The headlight system generates where there are other road users a shadow or a non-illuminated partial area in the high-beam area of the light distribution, so that they are not dazzled. Such partly shaded or in some other way partly darkened light distribution is also referred to in further text as partial high-beam distribution. Such headlight systems have been implemented in various embodiments in projection light modules with gas discharge lamps. In a projection system, an interior light distribution is generated inside the headlight, which is projected by a secondary lens system as an external light distribution into the outer space in front of the headlight. In the applicant's headlight used in a series, a twin-diaphragm system is operated by a stepping motor and a gear to produce in this way various forms of bright-dark boundary in the external light distribution of a low-beam function.
In addition to such adaptive low-beam function, this known module performs a high-beam function and with a diaphragm position also a partial high-beam function, in which in a module half a high beam is generated with a vertical bright-dark boundary, wherein the bright area of the half high beam is produced on the outer side of the vehicle, and on the vehicle inner side is produced a substantially horizontal bright-dark boundary.
Under a substantially horizontal bright-dark boundary we understand a bright-dark boundary which produces a legally compliant low-beam light. This is particularly the case when the angle enclosed by this light-dark boundary with the horizon is not greater than 30°. A more vertically than horizontally oriented light-dark boundary is in contrast characterized by the fact that the angle that it encloses with a vertical line, is smaller than the angle it encloses with a horizontal line.
By a horizontal pivoting of the entire light module (about a vertical axis), the horizontal position of the vertical bright-dark boundary can be varied. The interplay of the two projection light modules in the vehicle allows setting up the shadow position and the shadow width depending on the required driving situation. With the stepper motor drive, the switching speed between the different light distributions can be varied. So, for example, the switching speed between different light distributions, for example upon the activation and/or deactivation of the high beam or the partial high beam, can be defined with manual operation differently from an automatic control on the basis of an analysis of a camera image.
Also known are partial high-beam modules in which a movable diaphragm (hinged diaphragm), which is driven by an electromagnet, is activated. In one position of the movable diaphragm, a low-beam light distribution is generated in the light projection module, and in another position of the movable diaphragm a high-beam light distribution is generated which has a vertical bright-dark boundary. The horizontal position of the vertical right-dark boundary is changed by a rotation of the whole module. By pivoting apart the modules on both mounting sides, a shadow can be generated in the central area of the high beam. So it is a bi-function with horizontal rotation for positioning the vertical bright-dark boundary: only the low beam and the partial high beam can be produced. If one considers only one module, the full high-beam function is missing. This is much more advantageous compared to the above-described system. The full high-beam function is generated by the interaction of a right headlight and a left headlight.
In the case of the high beam, however, this results in a slight disadvantage for the driver, because the respective high beam light distribution is not quite complete. In the center in front of the vehicle the high-beam distributions are indeed superimposed, but on the right and on the left only the high beam of the respective module has an effect. Moreover, the relatively sharp vertical bright-dark boundary of the two modules is in the case of the full high beam in certain driving situations recognizable for the driver as a narrow, vertical stripe of greater brightness, which is bothersome.
DE 10 2009 008 631 A1 describes a projection light modules, which works with light-emitting diodes (LED) as a light source and, using a primary lens system, which generates the inner light distribution, and a secondary lens system, which serves projection optics, and generates a low-beam light and a high-beam light. Among other things, a diaphragm in the beam path of the high beam is described there, which by a largely vertically extending edge also allows the generation of the partial high beam with a vertical bright-dark boundary. Overall, there is described a module, which generates a low beam and a partial high beam without any mechanically adjustable diaphragm. For switching on high beam, only additional light sources must be switched on, and the additional vertical diaphragm automatically results in a partial high beam, which makes this module also a bi-functional light module.
The aforementioned DE 10 2011012 742 A1 describes a projection light module which with an array of reflectors and light-emitting diodes and a mirror diaphragm generates a low beam, and which in the high-beam operation can generate two partial high beams by an additional vertical diaphragm which is aligned along the direction of travel of the vehicle. By switching on and off the light sources of the two high-beam chambers separated by the vertical diaphragm, one can generate either a full high beam (as the sum of both partial high-beam distributions) or an only right-bright or only left-bright partial high-beam light distribution by switching on only the light source of one of the two high-beam chambers. The vertical diaphragm between the partial high-beam chambers may be coated with light-reflective material.
The high-beam diaphragm is placed such that the two high-beam chambers are situated axis-symmetrically to each other in relation to a vertical line extending through the HV point, wherein the vertical bright-dark boundaries which arise as images of the vertical diaphragm, lie on the vertical.